In arriving at a diagnosis a medical radiologist typically relies to a large extent, often entirely, on a visual study of silver images in radiographic films. Image inspection usually occurs with the film mounted on a light box, a white, translucent illumination source. To facilitate an accurate diagnosis a number of varied images are usually mounted and studied together.
Factors in addition to the characteristic curve parameters, such as minimum and maximum densities and contrasts in different curve regions, that significantly influence radiographic film selection by a radiologist include the following:
First, the radiographic element must be capable of producing images with minimal distracting artifacts. Artifacts include non-uniformities that run the risk of being mistaken for image features, produce visual fatigue, or are aesthetically distracting or displeasing, even when they have no proven impact on diagnosis.
Second, the radiographic element must be capable of rapid (less than 90 seconds overall) processing and, to an increasing extent, quick (less than 45 seconds overall) processing. Historically, a rapid processing capability has been acceptable, but to an increasing extent radiologists are requiring a quick processing capability.
Dickerson and Childers U.S. Pat. No. 5,041,364 disclose an approach for reducing surface glare in a medical diagnostic radiographic film (and thus visual fatigue). This is accomplished by overcoating an image forming layer unit including a silver halide emulsion layer coated on a support with an overlying layer unit containing a tabular grain silver halide emulsion. The tabular grains have a mean ECD of greater than 1.5 .mu.m and a tabularity of greater than 25.